The present invention generally relates to semiconductor elements, such as capacitors, and to methods of creating semiconductor elements. More specifically, the present invention relates to capacitors, such as metal-insulator-metal (MIM) capacitors, and to methods of creating MIM capacitors.
Capacitors are elements used extensively in electronic devices, such as in semiconductor devices, for storing an electric charge. Capacitors essentially comprise two conductive plates separated by an insulator. Capacitors are used in filters, analog-to-digital converters, memory devices, various control applications, mixed signal and analog devices, and many other types of semiconductor devices, for example.
One type of capacitor is a MIM capacitor (MIMcap). Capacitors featuring a metal-insulator-metal structure are commonly referred to as MIM capacitors. MIM capacitors are used to store a charge in a variety of semiconductor devices, such as mixed signal and analog products, for example. MIM capacitors are also used as RF capacitors in high frequency circuits. MIM capacitors are also often used in integrated circuits, as, for example, decoupling capacitors for microprocessor units (MPU's).
MIM capacitors come in various configurations. For example, both horizontally-oriented MIM capacitors (horizontal MIM capacitors) and vertically-oriented MIM capacitors (vertical MIM capacitors) are known. A horizontal MIM capacitor typically comprises a bottom conductive plate formed in a metallization layer and a top conductive plate formed in a layer overlying and in registry with the bottom conductive plate. The top conductive plate and the bottom conductive plate are separated from each other by a capacitor dielectric element.
Because most horizontal MIM capacitors have this layered structure, separate lithography and etch steps are typically employed to form the bottom conductive plate and the top conductive plate. These separate lithography and etch steps may, for example, require use of two masks, two lithography steps, and two etch steps, one each for the bottom conductive plate and the top conductive plate. Besides requiring extra resources, use of separate lithography and etch steps for formation of the bottom conductive plate and the top conductive plate also require extra measurement to ensure proper mask placement in preparation for forming the top conductive plate in registry with the bottom conductive plate. The extra measurement issue is even more pronounced when simultaneously forming the top conductive plate and vias to interconnect layers.
Existing methods for forming MIM capacitors have beneficially advanced the knowledge base regarding MIM capacitor manufacture. However, a need nevertheless remains for more efficient and cost effective MIM capacitor manufacturing processes that reduce process complexity, as compared to prior art MIM capacitor manufacturing processes. The present invention provides such a MIM capacitor manufacturing process that is more efficient and cost effective and reduces MIM capacitor manufacturing process complexity.